Connector for shielded cables

Abstract: A connector for shielded cables comprises a housing and signal and ground contacts mounted in said housing, said housing having an upper wall with inlet openings for the cables. A strain relief member for each cable joins an inlet opening, each strain relief member being unitary with the upper wall of the housing and projecting from said upper wall, wherein the shape of each strain relief member is adapted to the outer jacket of the corresponding cable.

Description: The invention relates to a connector for shielded cables according to the preamble of claim 1. In the known connectors of this type problems occur with respect to providing a strain relief for the cables connected to the connector. In a shielded cable, like a coaxial or twinaxial cable, the impedance of the cable is also determined by the dielectric lying between the signal conductor and the shielding. In shielded cables of high quality this dielectric consists of a relatively soft plastic material so that deformation of this plastic material easily occurs if high strain or compressing forces are exerted on the cable. This deformation results in a change of the impedance which adversely affects the transmission characteristics of the cable for high frequency signals. US-A-4 605 276 discloses a connector for shielded cables according to the preamble of claim 1. In this known connector a further housing is provided in which the housing with signal and ground contacts can be inserted together with two separate strain relief member halves. The strain relief member halves are held together by a PVC pipe cement compatible with the outer coating of the cable. The invention aims to provide a connector of the above-mentioned type, wherein a strain relief is provided in a simple manner such that deformation of the dielectric plastic material of the cable can be controlled. To this end the connector according to the invention is characterized by the characterizing features of claim 1. Thereby, a connector is obtained which is provided with a strain relief member being unitary with the housing of the connector and while joining the inlet opening for the cable extends along a part of this cable, so that the forces exerted on the cable are distributed along a large surface of the outer jacket of the cable, whereby deformation of the dielectric plastic material can be controlled. The invention will be further explained hereinafter by reference to the drawings, in which some embodiments of the connector according to the invention are shown. Fig. 1 schematically shows a perspective view of a first embodiment of the connector according to the invention in a partially disassembled position. Fig. 2 is a perspective view of the connector of Fig. 1 in its assembled position. Fig. 3 is a perspective view of three connectors according to Fig. 2 being plugged into a corresponding coupling socket. Fig. 4 is a perspective view of a part of the upper wall of the connector of Fig. 2, wherein for the sake of clarity the cables are not shown. Fig. 5 is a perspective view of a part of the upper wall of an alternative embodiment of the connector according to the invention in a not yet completely assembled situation. Fig. 6 shows the part of the connector of Fig. 5 in an assembled situation. Fig. 7-9 show a perspective view of a part of the upper wall of a third embodiment of the connector according to the invention in successive steps of assembly of the connector. Fig. 10-13 show a perspective view of a fourth embodiment of the connector according to the invention. Fig. 14 shows a perspective view of a fifth embodiment of the connector according to the invention in disassembled position. Fig. 15 shows a perspective view of a sixth embodiment of the connector according to the invention in disassembled position. Fig. 16 shows the connector of Fig. 15 in a partially assembled position. Fig. 17 shows a detail of the connector of Fig. 16. Fig. 18 shows a perspective view of the clamping element of the connector of Fig. 14 in two positions. Fig. 19 shows a perspective view of the clamping element of the connector of Fig. 15 in two positions. Fig. 1-3 show a first embodiment of the connector according to the invention, which connector 1 is provided with a housing 2 made of insulating material. This housing 2 is assembled of a module cap 3 wherein three modules 4 are detachably mounted in this module cap. The construction of the housing 2 is further described in a patent application of the applicant of the same date. For a further explanation of the construction of the housing reference is made to this patent application. Fig. 4 shows a part of the upper wall 5 of the housing 2 in more detail. Fig. 4 shows that the upper wall 5 is provided with inlet openings 6 for feeding shielded cables 7 into the housing 2, said cables 7 being made as cables with a differential pair of signal conductors 8 in this case. The signal conductors 8 together with a ground or drain wire 9 are enclosed by a metallized foil 10 working as a shielding. An insulating jacket or outer jacket 11 is provided around the foil 10. The signal conductors 8 are insulated with respect to the shielding 10 by a plastic sheath 12 forming the dielectric determining the impedance of the cable. This plastic material is relatively easily deformable whereby the impedance of the cable 7 could be affected. For this reason the strain relief of the cables 7 with respect to the housing 2 should be provided in a careful manner. To this end the housing 2 is provided with strain relief members which in this embodiment each are made as a support 13 being unitary with the upper wall 5 of the housing and projecting from this upper wall along a part of the length of the cable 7. The support 13 has a support face 14 at both sides smoothly joining the inner wall of the corresponding inlet opening 6. The shape of the support face 14 is adapted to the shape of the insulating jacket 11 of the corresponding cable 7. Due to the described shape of the supports 13 the forces on the cable 7 are distributed along a large surface, whereby deformation of the dielectric material 12 can be avoided in a controlled manner. In the embodiment of Fig. 1-4, the two cables adjacent one support 13 are pressed on the support faces 14 by means of a shrink sleeve 15. In Fig. 5 and 6 a part of the upper wall 5 of a second embodiment of the connector is shown, which is made mainly in the same manner as the connector 1. In this case a filling ring 16 is provided around the two cables 7 adjacent the same support 13, said filling ring consisting of a material with a high friction with respect to the outer jacket 11, like rubber, for example. The filling ring 16 is pressed on the outer jacket 11 of the cables 7 by means of a clamping strip 17. Fig. 7-9 show a part of the upper wall 5 of a third embodiment of the connector according to the invention, which is mainly made in the same manner as the connector 1. In this case the supports 13, one of which is shown in Fig. 7-9, are provided at their ends with an extension 18 in which passage slots 19 for a clamping strip 20 are provided. Further, a flexible support 21 is provided opposite each support face 14 of a support 13 at the other side of the corresponding inlet opening 6 in this embodiment, said flexible support 21 also having a support face 22 adapted to the shape of the outer jacket 11 of the corresponding cable 7. In Fig. 8 the cables 7 are schematically indicated and the clamping strip 20 is already provided but not yet tightened. As can be seen in Fig. 7 and 8, a gap 23 is provided between the end edges of the flexible support 21 and the end edges of the corresponding support face 14 of the support 13. In the tightened position of the clamping strip 20 shown in Fig. 9, the gap 23 at the upper side of the flexible support 21 is closed, whereby the pressing forces on the outer jacket 11 of the cables 7 are limited. Thereby, the compression of the insulating material of the cable is restricted and the clamping force is limited. Fig. 10-13 show a fourth embodiment of the connector according to the invention which is provided with a housing 2 assembled of a module cap 24 and modules 25. The upper wall 5 of the housing 2 is provided with supports 13 with support faces 14 joining the inlet openings 6 in the described manner. As pressing member a clamping plate 26 is provided in this embodiment having a passage 27 for each support 13 and corresponding cable 7. Each passage 27 has an inner wall part 28 pressing the cable 7 against the support face 14 of the support 13. The clamping plate 26 is provided with locking edges 29 at its longitudinal sides, said locking edges 29 cooperating with complementary locking edges 30 formed at the upper side of the module cap 24. At both longitudinal ends the clamping plate 26 is provided with a lip 31 which is received in a recess 32 at the upper side of the module cap 24 when the clamping plate 26 is mounted on the cap. In Fig. 11 the clamping plate 26 is snapped on the upper side of the module cap 24 and in a first detail it is shown how the locking edges 29, 30 engage one on the other while in a second detail it is shown how a passage 27 with a support 13 provides a cavity in which the cable 7 is clamped. Fig. 12 and 13 show the manner for snapping the clamping plate 26 on the module cap 24 after first feeding the cables 7 through the passages 27 and then connecting the cables with the contact elements not shown in the housing 2. In Fig. 14 a fifth embodiment of the connector according to the invention is shown in disassembled position. Fig. 14 only shows a module cap 33 without corresponding modules, wherein a clamping element 35 comprising two identical parts 34 is shown. In this embodiment the supports 13 are provided with a support face 14 at both sides, which support face 14 joins an inlet opening 6 for a cable 7 in the described manner. The supports 13 join at their upper side an end plate 36 with passages 37 aligned with the inlet openings 6. Between the end plate 36 and the upper wall 5 of the module cap 33 a free space is provided for receiving the clamping element 35. The clamping element shown in Fig. 18a and 18b in an open inoperative position and a closed operative position, respectively, is provided with wall parts 38 adapted to the shape of the outer jacket of the cable 7. When the clamping element parts 34 are coupled with each other as shown in Fig. 18b in the space between the end plate 36 and the upper wall 5 of the module cap 33, the wall parts 38 press the cables against the support faces 14 of the supports 13, whereby the desired strain relief is obtained. Fig. 15 shows a sixth embodiment, of which the module cap 33 is made in the same manner. In this case a clamping element 39 is used shown in Fig. 19a and 19b in the open inoperative position and the closed operative position, respectively. This clamping element 39 consists of two parts 40 which are interconnected by a film hinge 31 and at the other side can be coupled with each other as shown. In Fig. 16 the clamping element 39 is mounted in the operative position between the end plate 36 and the upper wall 5 of the module cap 33. Fig. 17 shows a detail of the module cap 33 with mounted clamping element 35 or 39, respectively, wherein the cavity is shown which is provided by the support 13 and the opposite wall part 38 and in which the cable 7 is clamped. The invention is not restricted to the above-described embodiments which can be varied in a number of ways within the scope of the claims.

Claims: Connector (1) for shielded cables (7), said cables each having an outer jacket (11), said connector comprising a housing (2) with signal and ground contacts mounted in said housing, said housing having an upper wall (5) with inlet openings (6) for the cables and a strain relief member (13) for each cable joining an inlet opening, characterized in that each strain relief member is integrally formed with the upper wall (5) of the housing (2) and is projecting from said upper wall, wherein each strain relief member comprises a support (13) projecting from the upper wall and having a support face (14) adapted to receive the outer jacket of a cable, wherein a pressing member (15, 17, 20, 26, 35, 39) is provided, said pressing member being adapted to press a cable against the support face (14) of a strain relief member. Connector according to claim 1, wherein at least one of the supports (13) joins one of the inlet openings (6) at two opposing sides and comprises a support face (14, 22) at the two opposing sides for the outer jacket of a cable. Connector according to claim 1 or 2, wherein a filling ring (16) and a clamping strip (17) are adapted to be mounted around the support (14) and at least one cable. Connector according to claim 1 or 2, wherein the pressing member is adapted to enclose the support and at least one cable and is made as a shrink sleeve (15). Connector according to claim 1 or 2, wherein a flexible support (21) with a support face (22) for the outer jacket of a cable is provided opposite each support face (14) of a support (13) at the opposite sides of the corresponding inlet opening (6). Connector according to claim 5, wherein the end edges of each flexible support (21) are located at a predetermined distance from the end edges of the support face (14) of the opposite support (13). Connector according to claim 5 or 6, characterized in that the pressing member is made as clamping strip (20), wherein passage slots (19) for the clamping strip are provided in the support (13). Connector according to claim 1, 2, 5 or 6, wherein the pressing member is made as a clamping plate (26) with at least one passage (27) for receiving a support (13) and a cable, said passage having an inner wall part (28) adapted to press a cable directly or through the flexible support (21), respectively, against the support face (14) of the corresponding support (13). Connector according to claim 8, characterized in that the clamping plate (26) can be detachably locked on the upper wall of the housing. Connector according to claim 9, characterized in that the clamping plate (26) has passages for all supports (13) of the housing and at its longitudinal sides is provided with locking edges (29) cooperating with complementary locking edges (30) at the upper side of the housing. Connector according to claim 1, 2, 5 or 7, characterized in that the pressing member is made as a clamping element (35, 39) which is movable from an open, inoperative position to a closed, operative position, wherein the clamping element is adapted to enclose in its operative position at least one support (13) and one or more cables and is adapted to press with a wall part (38) a cable directly or through the flexible support (21), respectively, against the support face (14) of the corresponding support (13). Connector according to claim 11, characterized in that the clamping element (35, 39) is a common element for all supports of the housing. Connector according to claim 12, characterized in that an end plate (36) with passages for cables is provided on the supports (13), wherein an open space is provided between the end plate and the upper wall of the housing for receiving the clamping element (35, 39). Connector according to claim 11, 12 or 13, characterized in that the clamping element (35) consists of two identical halves (34) which can be detachably connected with each other. Connector according to claim 11, 12 or 13, characterized in that the clamping element (39) consists of two halves (40) which are interconnected at one side by a film hinge (41) and at the other side can be detachably connected with each other.

Inventors: CREELE EDDY KAMIEL, JONCKHEERE LUC, MORLION DANNY, VAN KOETSEM JAN PETER KAREL, CREELE, EDDY KAMIEL, JONCKHEERE, LUC, MORLION, DANNY, VAN KOETSEM, JAN PETER KAREL
Applicants: FRAMATOME CONNECTORS INT, FRAMATOME CONNECTORS INTERNATIONAL
Application year: 1994
Main classification: H01R13
IPC codes: H01R13, H01R4